Field of the Invention
The present invention is broadly concerned with improved apparatus for dewatering of various meat products, to enable use thereof in high quantities as a part of pet feed recipes. More particularly, the invention is concerned with such apparatus which makes use of a pair of tapered, converging, intermeshed, counter-rotating helical screws located within an apertured housing. Rotation of the screws serves to express water from meat, providing a relatively dry product for use in extrudable pet feed mixtures.
Description of the Prior Art
Traditionally, kibble-type pet feeds have been produced using extrusion equipment. This normally involves use of a preconditioner which serves to initially moisten and partially cook the feed mixture, including grains, starches, fats, and other minor ingredients. After preconditioning, the mixture is fed into an extruder where it is fully cooked and shaped by a finished product ready for drying and packaging.
In recent years, pet feed producers have sought to incorporate greater and greater quantities of fresh meat into the feed recipes. At relatively low levels of meat addition, the traditional extrusion processing technologies are suitable. However, when attempts are made to incorporate high levels of meat (e.g., greater than about 40% by weight), standard preconditioner/extruder equipment may not be adequate. One issue is that fresh meat products are very high in moisture, and thus the usual steps of moisture addition into the preconditioner and/or extruder renders the product too wet for successful extrusion.
In response to this problem, equipment manufacturers have designed specialized extrusion equipment to handle high-moisture feed recipes. Another alternative, however, is to dewater the meat before it is mixed with the other feed ingredients, thereby at least partially ameliorating the high-moisture problem. However, prior dewatering devices have not been capable of efficiently dewatering meat to a low enough level for effective use in pet feed recipes.
References of interest include the following: U.S. Pat. Nos. 2,567,219, 4,438,691, 4,565,124, 4,935,183, 5,232,280, 5,333,556, 5,628,560, 5,694,883, 6,234,661, 6,609,819, 6,688217, 6,805,480, 7,191,700, 7,322,738,7,632,006, 7,731,879, 8,079,747, 8,596,856, and 9,316,439; US Patent Publications Nos. 2005/0219943 and 2008/0069916; Foreign Patent References Nos. CN101103825A, CN101531054A1, CN102225317A1, CN102275285A1, CN102490340A1, CN201439223U1, CN202062635U1, DE10113949A1, EP0358837, and WO2004080704; and non-patent publications: Baldwin, Adding flexibility to the extrusion process, Animal Feed, 2007; Bharath, Design of Twin Screw Oil Expeller for Pongamia Pinnata Seeds, International Journal of Emerging Technology and Advance Engineering, 2014; MLA Report, Evaluation and development of high moisture extruded red meat trim products, 2011; and JSW brochure, Twin Screw Extruder, 2014.